Staff at the Savanna South African deli in Southfields, in south-west London, seemed to be bracing themselves for a flood this week. Piled up behind the door were sacks and sacks of charcoal briquettes, and a van had just delivered enough boerewors sausages to sustain a carnivorous army.

Michele Hanson: At times like this, in boiling weather, when the picnic detritus rots and stinks and the wreckers come out to play, I long for a repressive regime to patrol parks, arrest slob picnickers and clap them into rubbish-collecting chain gangs.